High Energy Physics - Theory

Title:
The nonperturbative closed string tachyon vacuum to high level

Abstract: We compute the action of closed bosonic string field theory at quartic order
with fields up to level ten. After level four, the value of the potential at
the minimum starts oscillating around a nonzero negative value, in contrast
with the proposition made in [5]. We try a different truncation scheme in which
the value of the potential converges faster with the level. By extrapolating
these values, we are able to give a rather precise value for the depth of the
potential.

Comments:

24 pages. v2: typos corrected, clarified extrapolation in scheme B, and added extrapolated tachyon and dilaton vev's at the end of Section 3